Hi,
I bind a command to a button through command property and doing a command binding in
the page it is placed. In execute method I create an instance of a class that contains
the background worker and I start it (this is a long task).
The background worker (bw) class contains a variable isRunning that it is set to true before DoWork method is executed and to false when RunWorkerCompleted is executed. So from
the code
behind of
the page where button is placed, in CanExecute method I set e.canExecute to true if bw is no running (isRunning = false), and e.canExecute to false if isRunning = true.
WHen I press
the button, it launch bw process for a long time and
the button gets disabled. Ok this is correct, but when background worker (bw) finishes,
the button doesn't returns to enabled until I press it again. When it is disabled and I press (when bw is finished) it gets enabled. Why
the button is not returning automatically to enabled at
the end of
the bw?
my code snippet:
<Page x:Class="GParts.Pages.MyPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;
assembly=PresentationFramework.Aero"
xmlns:local="clr-namespace:GParts"
Loaded="Page_Loaded"
Unloaded="Page_Unloaded"
Height="Auto">
<Page.CommandBindings>
<CommandBinding Command="{x:Static local:Pages.MyPage.rcmd}"
Executed="CommandBinding_Executed"
CanExecute="CommandBinding_CanExecute"/>
</Page.CommandBindings>
<...>
<Button Command="{x:Static local:Pages.MyPage.rcmd}" />
<...>
</Page>
The code
behind of
the page:
namespace GParts.Pages
{
public partial class MyPage : Page
{
public static RoutedCommand rcmd = new RoutedCommand();
private cBgWorker bw;
<...>
// ExecutedRoutedEventHandler for
the custom button remove all command.
private void CommandBinding_Executed(object sender, ExecutedRoutedEventArgs e)
{
// get an isntance of
the background worker class
bw = new cBgWorker();
// start
the long task
bw.StartTask();
}
// CanExecuteRoutedEventHandler for
the custom button remove all command.
private void CommandBinding_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
// bw is
the instance of background worker class
if (bw == null)
{
e.CanExecute = true;
}
else
{
e.CanExecute = !bw.isRunning;// isRunning indicates if bw is
//executing now
}
}
<...>
} // end class
} // end namespace
